What do you want to do with it? If you want bigger tires and offroad capability it will probably pay dividends to shorten it up. You gain everywhere. If its for general use you get into too short of a wheelbase to haul, stop, or carry anything which makes it useless. No one is swapping in one ton drivelines to Blazers to make them workhorses.
Useless can be a relative term. Take an over the road tractor running bobtail, for example. It can't haul anything other than the trailers it was designed to pull, doesn't stop worth a **** (especially the older ones without front brakes), and the ride is not good even with air suspension.
Yet most everything we own has been brought by a tractor trailer, so while the tractor is somewhat useless by itself, it's perfect for pulling semi trailers.
In a way, my shortened 1008 is like a miniature over the road tractor. Not good for "general use", as you put it, but much, much better suited for the trailer pulling duty it was modified to do. So, yes, it all depends on what the goal is.
It was very close that the M1009 ended up in this trailer pulling role. It was already short and had the mechanical upgrades, but it sold before the 1008 did. In retrospect, that was a good thing. The Blazer's frame probably wouldn't have liked its new job.
Overall, I suppose that it's like any four wheel drive that gets modified; the more trail worthy it becomes, the less pavement friendly it tends to get.